Wall-board-joint system



Feb. 26, 1929. 1,703,667

1 E. GREEN WALL BOARD JOINT SYSTEM Filed se t. 24, i927 Patented Feb. 26, 1929.

UNITED STATES PATENT OFFICE.

ERNEST GREEN, 0]? NORTH ENGLISH, IOWA, ASSIGNOR T0 UNITED STATES GYPSUM 00., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

WALL-BOARD-JOINT SYSTEM.

Application filed September 24, 1927. Serial No. 221,845.

This invention relates to an improvement in uniting sectional wall and ceiling finish units, to afford a continuous monolithic-like smooth surface which can be painted, calci mined, or papered all over, directly without previous plastering or leveling up coat.

There are several fairly common methods of preparing wall or ceiling surfaces with plaster and fibrous wallboards to receive various brush decorative coats without the neces sity of putting on a plastering coat prior thereto. The essential features of all of these methods is the effectual concealment of the joints between the various units. Ordinarily the wallboards are erected upon studding, or furring strips, each board extending the full distance between the floor and the ceiling on side walls and so erected on ceilings to give the smallest number of joints.

Of the various methods of concealing the joints paneling with wooden battens is well known, but this method does not yield expansive monolithic-like surfaces and is often objectionable from the decorative standpoint.

The use of a cementing filler only between the boards to conceal the joints is also not satisfactory since it lacks permanence and develops cracks which come through the decora-.

tion, thus the wall soon becomes unsightly. The use offabric tapes or canvas as a joint reinforcement does not completely eliminate later joint cracking, and in addition such treatment often shows discoloration 'at the joint due to the unequal obsorotion of the decoration by the fabric and the wallboard.

Wire mesh fabric or expanded metal fabric are even more unsatisfactory from a decorative standpoint. Such metal fabrics to be substantial are so thick, that they demand a plastering coat with a trowel for they cannot be concealed with ordinary thinner decorative coats applied with a brush. These types of metal fabric can only be used with a heavy and textured decoration since their considerable thickness is exceedingly difficult to conceal, on a continuous unbroken monolithic-like wall surface.

to cause failure in some thin decorations. Also joint filler or joint cement undergoes volume change during the setting and drying and thus will induce a corresponding movement in the adjacent wallboard. If a cloth fabric is used, it stretches in expansion and then correspondingly bulges when the board returns to its original place. The difficulty of concealing the necessarily thick wire fabric has been mentioned. In addition, these being woven move easily in a torsional or bias direction and thus while the boards are reinforced at right angle tension, there is opportunity for the board to move up and down on the supporting members with similar acany decoration may be applied without the joint being noticeable.

Reference is to .be had to the accompanying drawing forming a part of this specification in which the figure is a perspective view of my improved wallboard joint systenn My system differs from the similar systems now in use in the material used by which a. joint of superior strength is obtained with a joint reinforcing mediumso extremely thin that it is unnoticeable through the subsequent decoration. I have found however, that to be successful in making a secured joint the reinforcement used must be strong enough to resist all shearing stresses produced by board movement, must be able to resist the bulging action'of the cement and joint filler compound, must have sufficient rigidity to overcome torsional or bias stresses, and must be stanch enough toresist other normal move ments of such a wallboard through changes of humidity and temperature. In addition the .finished joint must be so thin in character,

that is, it must scarcely protrude above the level surface of the wall so that-1t can be easily concealed and not show through the ness of only .002 of an inch. It has been.

noted that about the smallest crack that is visible is .005 inch and I prefer to keep my joint reinforcing medium substantially within that thickness. After the wallboards 6 are in place the joints are filled with a suitable adhesive cemcntitious joint filler 7 which spreads sufiiciently to cover the area over.

which the ribbon is applied. The ribbon of this thin metal foil is then placed over the joints and cementitious adhesive and smoothed down, thus concealing the joint and leaving a substantially smooth continuous monolithic-like surface for the application of adecoration of any desired nature.

For the above mentioned thin metal foil I prefer to use a rustproof or non-corrosive metal. A vcommercial alloy known as Toncan steel is satisfactory. I have secured this and applied it in a foil only .002 inch thick and still have maintained sufiicient strength to give a joint so reinforced that it had a tensile strength in excessof 100 pounds per lineal inch. Foil under .005 of an inch is sufficiently thin to apply easily without kink- Y ing or injuring the hands like wire mesh fabric does with its twisting and scratching of the loose frayed ends, and such foil will maintain the requisite strength and offer sufficient concealment. because of its thinness. Other metals may be used if they are available and strong enough, such as the ordinary soft metals like zinc which is preferably alloyed. with other metals so as to have the strength, when sufficiently thin to be easily worked, and thus conceal and effectively reinforce the joint and prevent subsequent cracking.

To assist any moisture in the cementitious adhesive to escape andthus expedite drying, and to facilitate mechanical bond between the thin metal foil and the wallboard, I prefer to perforate the foil in a-casual way. The perforations 8 may take the form of holes of any shape so spaced that they leave sufiicient tensile strength across the reinforced joint. These perforations are not primarily for mechanical bond but rather for expediting the set of the cementitious adhesive, byfacilitating moisture escape, since mechanical bond may be obtained in other ways such as mill frosting or emery embossing on the metal foil itself. But it is appreciated that this latter, while effective as a mechanical bond does not readily facilitate the escape of moisture in the filler cement and does not hasten the setting and drying like a few casual perforations in the foil would, further mill frosting and emery embossing reduce the strength more than casual perforations.

Having thus described my invention, what I claim is: t

1. In a wall construction, the combination with wallboards having the edgesthereof attached to supporting framework in substantially abutting relation to form a wallboard joint, of a strip of thin metallic foil having perforations extending along said joint for reinforcing same, said strip being secured to the wallboard by a joint filler plastic cement, the whole being concealed by a paint-like substance.

2. In a wall construction, the combination with wallboards having the edges thereof attached to supporting framework in substantially abutting relation to form a wallboard joint, of a strip of metal foil having a thickness of 0.0020.008 inches extending along said joint for reinforcing same, said strip being securely attached to the wallboards by joint filler plastic material which also effectually conceals the edges of said strip.

In a wall construction, the combination with wallboards having the edges thereof in substantially abutting relation to form a wallboard joint, of a thin strip of metal foil extending along said joint for. reinforcing same, said strip being rigidly secured to said wallboards by joint filler plastic adhesive,

said strip being provided with perforations to permit the uniform drying of the plastic material under said strip. v

4. In a wall construction, the combination with wallboards having abutting edges to form a joint, of a strip of thin foil composed of a zinc alloy, said strip extending along the joint and being secured to the wallboards by joint filler plastic material, said strip being provided'with a series of perforations adapted to permit the drying of said plastic therethrough.

-In witness whereof, I have hereunto subscribed my name.

ERNEST GREEN. 

